[RFC v2 12/12] i386: Support custom topology for microvm, pc-i440fx and pc-q35

[Zhao Liu <zhao1.liu@xxxxxxxxx>]

With custom topology enabling, user could configure hyrid CPU topology
from CLI.

For example, create a Intel Core (P core) with 2 threads and 2 Intel
Atom (E core) with single thread for PC machine:

-smp maxsockets=1,maxdies=1,maxmodules=2,maxcores=2,maxthreads=2
-machine pc,custom-topo=on \
-device cpu-socket,id=sock0 \
-device cpu-die,id=die0,bus=sock0 \
-device cpu-module,id=mod0,bus=die0 \
-device cpu-module,id=mod1,bus=die0 \
-device x86-intel-core,id=core0,bus=mod0 \
-device x86-intel-atom,id=core1,bus=mod1 \
-device x86-intel-atom,id=core2,bus=mod1 \
-device host-x86_64-cpu,id=cpu0,socket-id=0,die-id=0,module-id=0,core-id=0,thread-id=0 \
-device host-x86_64-cpu,id=cpu1,socket-id=0,die-id=0,module-id=0,core-id=0,thread-id=1 \
-device host-x86_64-cpu,id=cpu2,socket-id=0,die-id=0,module-id=1,core-id=0,thread-id=0 \
-device host-x86_64-cpu,id=cpu3,socket-id=0,die-id=0,module-id=1,core-id=1,thread-id=0

Signed-off-by: Zhao Liu <zhao1.liu@xxxxxxxxx>
---
 hw/i386/microvm.c    | 1 +
 hw/i386/pc_piix.c    | 1 +
 hw/i386/pc_q35.c     | 1 +
 hw/i386/x86-common.c | 6 ++++++
 4 files changed, 9 insertions(+)

diff --git a/hw/i386/microvm.c b/hw/i386/microvm.c
index dc9b21a34230..bd03b6946e6c 100644
--- a/hw/i386/microvm.c
+++ b/hw/i386/microvm.c
@@ -671,6 +671,7 @@ static void microvm_class_init(ObjectClass *oc, void *data)
     mc->reset = microvm_machine_reset;
 
     mc->post_init = microvm_machine_state_post_init;
+    mc->smp_props.custom_topo_supported = true;
 
     /* hotplug (for cpu coldplug) */
     mc->get_hotplug_handler = microvm_get_hotplug_handler;
diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
index c1db2f3129cf..9c696a226858 100644
--- a/hw/i386/pc_piix.c
+++ b/hw/i386/pc_piix.c
@@ -473,6 +473,7 @@ static void pc_i440fx_machine_options(MachineClass *m)
     m->no_floppy = !module_object_class_by_name(TYPE_ISA_FDC);
     m->no_parallel = !module_object_class_by_name(TYPE_ISA_PARALLEL);
     m->post_init = pc_post_init1;
+    m->smp_props.custom_topo_supported = true;
     machine_class_allow_dynamic_sysbus_dev(m, TYPE_RAMFB_DEVICE);
     machine_class_allow_dynamic_sysbus_dev(m, TYPE_VMBUS_BRIDGE);
 
diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c
index 9ce3e65d7182..9241366ff351 100644
--- a/hw/i386/pc_q35.c
+++ b/hw/i386/pc_q35.c
@@ -356,6 +356,7 @@ static void pc_q35_machine_options(MachineClass *m)
     m->max_cpus = 4096;
     m->no_parallel = !module_object_class_by_name(TYPE_ISA_PARALLEL);
     m->post_init = pc_q35_post_init;
+    m->smp_props.custom_topo_supported = true;
     machine_class_allow_dynamic_sysbus_dev(m, TYPE_AMD_IOMMU_DEVICE);
     machine_class_allow_dynamic_sysbus_dev(m, TYPE_INTEL_IOMMU_DEVICE);
     machine_class_allow_dynamic_sysbus_dev(m, TYPE_RAMFB_DEVICE);
diff --git a/hw/i386/x86-common.c b/hw/i386/x86-common.c
index 58591e015569..2995eed5d670 100644
--- a/hw/i386/x86-common.c
+++ b/hw/i386/x86-common.c
@@ -195,6 +195,12 @@ void x86_cpus_init(X86MachineState *x86ms, int default_cpu_version)
     }
 
     possible_cpus = mc->possible_cpu_arch_ids(ms);
+
+    /* Leave user to add CPUs. */
+    if (ms->topo->custom_topo_enabled) {
+        return;
+    }
+
     for (i = 0; i < ms->smp.cpus; i++) {
         x86_cpu_new(x86ms, i, possible_cpus->cpus[i].arch_id, &error_fatal);
     }
-- 
2.34.1